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If this application takes off, I have to presume that everyone's baseline network usage metrics can be tossed out the window...

That'll happen anyway, what used to be considered high volume content is becoming the norm with lots of start ups and old school broadcasters getting involved.

P2P is a bandwidth sharing mechanism

And a way to put off addressing the problem. We've been using it for VOD but we really do want people to do multicast for live TV (http://support.bbc.co.uk/multicast). It also exposes home PCs to more exploits by 3rd parties. Previously it was only our own servers we put at risk

As streaming video takes off, it will use more or less the same amounts of bandwidth, P2P or no, as long as the underlying transport is unicast

ISPs might dislike peering with content providers, creating massive uncontrolled P2P gets round that at their expense. We've avoided trying to make unicast too big but we have content that many millions use (concurrently) that won't stay away

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It downloads 320 megabytes (MB) per hour from users' computers, meaning that users could reach their monthly download limits in hours and that it could be unusable for bandwidth-capped users.

Our multicast streams are 360K for legacy users but 1.2M, 3-5M (full DTV quality same as off air) and 18M (HD, the encoders aren't mature yet, may be down to 8M this summer. Less is possible but 2Mbit isn't HD in any codec yet if you want it to be good) At the higher rates P2P over current UK ADSL (gain < 1) is going to need a lot of benevolent users willing to donate b/w when they're not active. brandon